Industrial-scale gas separation can be performed using various techniques that allow for the enrichment or actual separation of a gas of interest. Swing adsorption techniques are based on processes in which controlled cycling of an experimental parameter allows for differential adsorption and release of a gas in a medium. Pressure swing adsorption (PSA) pressurizes and depressurizes gas around an adsorbent media to selectively adsorb certain components of a gas, allowing others to be selectively discarded. Vacuum swing adsorption (VSA) uses the same general principle as PSA, but swings between vacuum pressures and atmospheric pressure. The two techniques may be combined, and are called “vacuum pressure swing adsorption” (VPSA) in this case. Further, temperature swing adsorption (TSA) uses a similar technique to other swing adsorption techniques but cycles temperature instead of pressure. Cryogenic distillation is typically only used for very high volumes because of its nonlinear cost-scale relationship, which makes the process more economical at larger scales. Membrane technologies are not as well-developed as other gas separation techniques and as a result they are less widely used. Partially permeable membranes allow “fast” gases to pass through and be removed, while “slow” gases remain in the airstream and emerge without the original contaminants. However, manufacturing challenges mean the units are better suited for small to mid-scale operations.
PSA and TSA are often used in industrial settings, but have significant disadvantages, especially high energy consumption. This often prevents cost-effective large-scale gas separations, such as Gigaton-level carbon dioxide capture from the flue gas of coal-fired power plants. In fact, separating CO2 from flue gas with known established PSA or TSA techniques would consume >30% of the power of a power plant. That large energy consumption would increase (about double) the price of electricity. Electrical and electrochemical approaches have been considered as alternative techniques to the classical PSA and TSA technologies. However, the techniques known in the art suffer from similar problems as TSA and PSA, namely, that there is a permanent electrical current flow which consumes a large amount of energy.
There is thus a need in the art for novel devices and methods that allow for energy-efficient gas separation in industrial scale. The present invention addresses this need.